If at first you don't succeed, dig a new test bed Good thing to have, my garden's far too trashy or I would certainly do one. I did sort of copy (re-jig) one of your test bed ideas, I took a large plastic bucket of soil off my favourite site and learned a hell of a lot with that bucket at the bottom of the garden.

You could have some real fun with that one Gary. Tell them you have found an old map that shows lost treasure on their land. When you start taking it out the hole scream "It's the lost treasures of King Arthur !!" Imagine their faces